1. Field of the Invention
The invention relates to a radio or television receiver for receiving a plurality of signals, comprising selection means for selecting a selected signal and identifying means for assigning an identity to each signal.
2. Description of the Related Art
Such a receiver is widely known. For example, a television receiver (or VCR) comprises tuning means for selecting a TV signal from a plurality of TV channels. Similarly, a radio receiver can tune to a specific radio signal. Such receivers often feature a mechanism for assigning an identity to each channel for the purpose of displaying the selected channel, or enabling a user to select a particular channel. For example, preset numbers are used to identify a channel. The invention also relates to a television receiver comprising teletext means, enabling a user to select a particular page from a plurality of pages, each of which is identified by a unique page number.
Often, users want to return to signals which were visited previously, e.g., when the user wants to match TV programs from a couple of channels at the same time, or when some teletext pages comprise mutually related information. However, this is no trivial task with current radio and television receivers. Users have to remember the identity of a signal they will possibly want to return to in the future, and enter the identity correctly when they actually want to return to the signal. There are TVs exist which offer the possibility to store identities in a xe2x80x98favorite listxe2x80x99. However, this requires the user to perform explicit actions for storing and removing identities, and such lists need to be updated regularly.
It is an object of the invention to provide a radio or television receiver which allows easy access to previously selected signals.
To achieve this object, the radio or television receiver according to the invention is characterized in that the receiver further comprises history means for automatically keeping a history list of signal identities in response to a succession of signal selections, the history means further comprising navigation means for changing a current position in the history list and generating a control signal for the selection means to select a signal corresponding to the identity at the current position. Such history means automatically store identities of signals which have been selected recently, and enable the user to easily recall these signals.
In an embodiment, the history means are further adapted to impose an order upon the history list, the navigation means further comprising backward means and/or forward means for changing the current position to a position which precedes or succeeds the current position in accordance with the order. By imposing such an order on the identities in the history list, a simple mechanism can be applied to access all identities in the list, by consistently traversing the list in one or two directions by means of said backward means and/or forward means. In a preferred embodiment, the signal identities in the history list are substantially ordered by ascending recency of storage in the history list. In this way, the signals selected most recently are at the end of the list and can be selected with minimal effort by operating said backward means.
In a further embodiment, the history means further comprise discrimination means for marking the selected signal as being relevant or irrelevant for including its identity in the history list, the history means being further adapted to include the identity of the selected signal only if the selected signal is marked as being relevant. By examining the selection behavior of the user, the history means attempts to deduce whether a particular signal is of current interest to the user, i.e., relevant for including its identity in the history list. Filtering less relevant signals from the history list further enhances the usability of the history means. Various embodiments, defining conditions for signals to be included in the history list, will now be disclosed.
TV channels or teletext pages which have been selected for some predetermined period of time are likely to be of current interest to the user, hence, in an embodiment, they are included in the history list. In a further embodiment, also channels which are selected by explicitly entering their identity, as opposed to zapping, are included in the history list. Most radio or television receivers impose a logical order on the identities of the plurality of signals and provide zapping means for traversing the identities in an ascending or descending direction. For example, presets are often assigned numbers, and said zapping means are generally implemented by an xe2x80x98upxe2x80x99 button and a xe2x80x98downxe2x80x99 button, which select a channel or a teletext page whose number is increased or decreased by one with respect to the number of the currently selected channel or page. Zapping through radio or TV channels is typically performed when the user has no specific intentions or expectations, so most channels selected this way are not likely to be of much interest to the user. In a radio or television receiver according to the invention, signals which are selected by means of the zapping means are not included in the history list, unless they have been inspected for said predetermined period of time.
In a further embodiment, which is particularly useful for teletext, a signal is included in the history list when it was displayed when another signal was selected by explicitly entering its identity. In a teletext system, this guarantees that index pages, comprising numbers of other pages which are likely to be entered explicitly by the user, are included in the history list, hence can be recalled easily.
A further condition for including an identity of a channel or teletext page in the history list is the operation of the navigation means when the channel or page is currently displayed. This guarantees that the channel or page can also be returned to by means of the navigation means. Optionally, the identity can be removed again after returning to it by means of the navigation means.
It is to be noted that television receivers are known which feature a dedicated button for selecting the previous channel. There are also television receivers which feature colored buttons for recalling two previously selected teletext pages which are indicated on the screen in corresponding colors. A drawback of such a feature is that only a very limited number of signals can be accessed and that disturbing elements are required on the screen.